Sugar sculpture is the art of producing artistic centerpieces entirely composed of sugar and sugar derivatives. These were very popular at grand feasts from the Renaissance until at least the 18th century, and sometimes made by famous artists. Today, there are many competitions that include sugar sculpture. Sugar showpieces can be composed of several different types of sugar elements. All begin with cooking sugar, and possibly an acidic agent and/or non-sucrose sugar product to avoid unwanted crystallization, to the hard crack stage, around . When all components are completed, they are welded together using a gas torch. The sugar is melted, and then joined together. Types Pulled sugar The sugar has been cooked, and the now-liquid sugar is poured onto a silicone rubber mat. Any coloring is now added. The sugar is then folded repeatedly into itself, until the sugar is, while still flexible, cool enough to handle. The sugar is then stretched out and then folded on itself repeatedly. This process incorporates air into the sugar, and gives it a bright lustrous sheen. The sugar can then be sculpted by hand into various shapes, made into ribbons, or blown. Blown sugar In blown sugar, a portion of pulled sugar is placed on a rubber pump which is tipped with either wood or metal. Pumps are most commonly hand pumps. While being blown, the sugar can be shaped, often into animals or flowers. Blown sugar cannot be quickly cooled by dipping it in water, so chefs must use fans to cool the sugar, all the while rotating it, so that it does not come out of shape. This technique is very useful in making balloons for wedding cakes. Cast sugar In this technique, sugar is poured into molds. This technique produces sturdier pieces than the pulled and blown sugar techniques do, and it is almost always used for the base and structural elements of showpieces. Cast sugar can also be used in many other recipes such as those for cakes. Pastillage A thick sugar paste, similar to gum paste, is molded into shapes. When dried, it is hard and brittle. Made with gelatin, water and confectioner's sugar, it hardens quickly and can be shaped for a short while by hand, and after hardening, with electric grinders, cutters, sandpaper and assorted files. Some recipes will contain an acid in the ingredients list, such as vinegar or cream of tartar. Pressed sugar